HORTSCIENCE 48(6):672–680. 2013. from the USDA Chico jujube program, se- lections from across the United States, and recent imports from China or other jujube- Past, Present, and Future of growing countries (Table 1). Those in Table 1 were listed as cultivars, but only a few of Jujubes—Chinese Dates them were formally named, released, and went through cultivar trials. in the United States Cultivars imported through Frank Meyer and the remaining cultivars currently in the Shengrui Yao1 United States. Frank N. Meyer reportedly Department of Plant and Environmental Sciences, Sustainable Agriculture made four trips to China (1905–08, 1909–11, Science Center at Alcalde, New Mexico State University, 371 County Road 1912–15, and 1916–18) (Plantexplorers.com, 2012). Locke (1948) mentioned that 83 of 40, Alcalde, NM 87511 2500 of Meyer’s PIs to the United States were Additional index words. Ziziphus jujuba, cultivar, biology, flowering, pests and diseases, jujubes. The author went through all the nutrition, propagation, fruit use, processing 1905–18 PI records (online now) and found that 67 jujube accessions were directly im- Abstract. This article summarizes jujube importation and culture history and current ported by Meyer from China (Table 2) (Gal- jujube cultivars in the United States. Described within are jujube taxonomy, biology, loway, USDA, 1907, 1908, 1909a, 1909b, adaptation, fruit nutrition, pests and diseases, propagation, and research conducted 1912; Taylor, USDA, 1916a, 1916b, 1917a, in the United States. It also discusses the current issues with jujubes in the United States 1917b, 1917c, 1922a, 1922b). Besides Frank and possible solutions to them. Jujube adapted and grew well in the southern and Meyer’s collection, others also collected 20 southwestern United States, and it could become a valuable industry in the United States jujube accessions from 1905 to 1918 with within 15 to 20 years. 14 from China, four from the United States, one from Paris, and one from Asia (Table 3) (Galloway, USDA, 1909c, 1910, 1911a, Jujube (Ziziphus jujuba Mill), also called and were used as a table dessert or winter 1911b, 1911c, 1911d; Taylor, USDA, 1914a, chinese date, red date, or tsao (zao), is native sweetmeat. 1914b, 1915, 1917a, 1917c, 1919). Later, to China (Liu, 2006; Qu, 1963). It originated Liu (2006) reviewed the jujube basics and those accessions were rarely mentioned in in the middle and lower reaches of the Yellow research in China and worldwide. Lyrene literatures. River and has been cultivated in China for (1979) briefly summarized the jujube tree Table 2 indicates that Meyer visited the more than 4000 years (Guo and Shan, 2010; situation in the United States. This review five major jujube-producing provinces in Liu, 2006). Botanically, it is derived from its focuses on the cultivar history, biology, adap- China: Hebei (formerly Chihli), Shandong, wild relative sour jujube or wild jujube (Z. tation, and production challenges in the United Shanxi, Shaanxi, and Henan Provinces as spinosa Hu). In ancient times, people se- States and makes a comparison with the jujube well as the Beijing and Tianjin areas. Frank lected and cultivated sour jujubes with big situation in China whenever necessary. Meyer collected roots or budwood of an fruit and good flavor, and it gradually became unknown big-fruited cultivar during his first the cultivated modern jujube species (Z. Jujube History in the United States trip in 1905, which possibly did not survive jujuba). There are still semicultivated sour because this was his first jujube import jujubes like ‘Tiger Eye’, big round, sour Robert Chisholm first brought jujube without any rootstock preparation, and the jujube, and Yanjishan big sour jujube, which seedlings to the United States and planted shipment itself may have been problematic. are popular in Beijing and Shandong Prov- them in Beaufort, NC, in 1837 (Rehder He sent back 12 batches of jujube seeds from ince, China, respectively (Guo and Shan, and Rixford, 1929). In 1876, G.P. Rixford jujube cultivars and sour jujube (Z. spinosa) 2010). brought jujubes from southern France to from 1905 to 1907. Some of those seeds were Jujube was first dispersed within China California’s Sonoma Valley and neighboring collected in Sept. 1907 from famous cultivars from its original center and then to coun- states (Rehder and Rixford, 1929). By 1901, like ‘Chin sze tsao’ (Jinsi zao in Chinese), tries bordering China. It was through the jujube had escaped from cultivation and ‘Yuen ling tsao’ (Yuanling zao), and two rare famous ‘‘Silk Road’’ that jujubes were in- naturalized along the Gulf Coast from Ala- flat cultivars like mini apples in Shandong troduced to Europe at the beginning of the bama to Louisiana (Bonner and Rudolf, 1974; Province. In Mar. 1908, Meyer collected bud- Christian era (Liu, 2006; Lyrene, 1979). It Lyrene, 1979). All of those early imports were wood for the famous ‘Lang’ and ‘Mu shing is widely distributed in Persia, Armenia, seedling plants from Europe, not vegetatively hong tsao’ together with ‘Hu ping tsao’ (Hup- Syria, Spain, and France (Locke, 1948; Lyrene, propagated cultivars. It was not until 1908 ing zao) and ‘Tsui ling tsao’ (Cuiling zao) 1979). Most early jujube imported to Europe that USDA agricultural explorer Frank from Shanxi Province. The USDA Chico were seedlings (Locke, 1955; Lyrene, 1979) N. Meyer introduced the first group of com- Station received them in 20 Apr. 1908, which mercial jujube cultivars directly from China opened a new era for jujubes in the United (Meyer, 1911). Meyer mentioned that one of States with big-fruited cultivars. the most promising tree crops of China was Meyer collected the major cultivars in Received for publication 1 Mar. 2013. Accepted for publication 2 Apr. 2013. the chinese jujube, and he predicted jujube each region, like ‘Chin sze tsao’, ‘Yuen ling This paper is partially supported by the USDA wouldbeofgreatvalueinthesemiaridsouth tsao’, ‘Lang tsao’, ‘Hu ping tsao’, and ‘Ta Specialty Crop Block Grant through the New and southwest United States (Meyer, 1916). tsao’ (big-fruited tsao) and ‘Hsiao tsao’ Mexico Department of Agriculture. This is also Jujube was one of two plants sculpted on the (small-fruited tsao). However, ‘Ta tsao’ and a contribution of the New Mexico Agricultural Frank N. Meyer Memorial Medal from the ‘Hsiao tsao’ are different from region to Experiment Station, New Mexico State University, American Genetic Association in recogni- region, which usually refer to the two local Las Cruces, NM. tion of his contribution to plant germplasm dominant cultivars, but they are different in I thank Steve Guldan, Richard Heerema, and Geno collection and use (Fairchild, 1920). size. He also collected some rare cultivars—a Picchioni from New Mexico State University for flat one resembling a mini apple, a seedless their critical review of the manuscript. I also thank Martha Davis from Los Alamos, NM, and Roger Jujube Cultivars in the United States (pitless) one named ‘Wu hu tsao’ (Meyer, Meyer from Fountain Valley, CA, for their com- 1911), ‘Yu tsao’ (Ya zao, tooth-shaped), ments and suggestions. The jujube cultivars in the United States a contoured one with gnarled and zigzagged 1To whom reprint requests should be addressed; now include several groups: Frank Meyer’s branches, ‘So’ (PI 37484), and another one e-mail [email protected]. direct imports from China, U.S. cultivars with crooked and twisted branches called
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Table 1. Current jujube cultivars in the United States. fruit quality scattered in people’s backyards Sources Cultivars without names. Locke (1948) mentioned that F.N. Meyer’s collection Li, Lang, Shui men (Shuimen, Sui men or Sui), Mu/Mu shing the patent office distributed jujube seeds to hong, So, Yu interested people in 1854. This is why there Chico breeding programy GA866, GI-7-62/Chico, GI-1183, Thornless are many cultivars from different states Cultivars from across the United States named after people or towns, which are the Alabama Silverhill,w Ed Hegard,w Swobadaw result of long-term selections from seedlings California Don Polenski,u Jin,u Porterville,u Redland #4,x Sugarcanex w w w or survivors of Frank Meyer’s imports. Some Georgia Fitzgerald, Leon Burk, Prine of them could be the same cultivar but were Florida Geantw Kansas Topekax found and renamed at other locations. Ge- Kentucky Priesty netic analyses are needed to clarify their Louisiana Abbeville,u Sherwoodz relationships. To date, there has not been Pennsylvania Tsaox much genetic or molecular work on jujubes Tennessee R3T1v for cultivar classification and grouping in the Texas Texas Tartu United States. Washington, DC Admiral Wilkesx Some cultivars from this group are of Imports after the 1990s y,u sufficiently high quality to be officially R. Meyer’s import Shanxi Li, Honeyjar, Globe, September Late, Ant Admire, named, but most of them lack regional tests. and Sihong J. Gilbert’s import Qiyuexian/Autumn Beauty,y Mango Dong Zho/Winter For example, ‘Sherwood’ (Atkins, 1987) was DelightTM,y Black SeaTM, CocoTM, etc. an excellent cultivar for California, Texas, NMSU Alcalde’s import Jinsi #2, Jinsi #3, Pitless, Junzao, Teapot, etc., with total of and Louisiana, but it has poor fruit set and 30 cultivars does not ripen before first frost in northern zAtkins, 1987. New Mexico. The author noticed several yAshton, 2006. jujube trees 30 to 50 years old or older across xCalifornia Rare Fruit Growers, 1996. New Mexico with good quality for both fresh wLyrene, 1983. eating and drying that would be worth further vOsborn and Miller, 2009. attention and testing. u Xotcfruit (R. Meyer), 2013. Recent imports from China and other jujube-growing areas. In California, Roger Meyer imported several cultivars from ‘Dragon’ or ‘Dragon’s-claw’ (Meyer, 1911). The observation and research work on ju- China’s Nanjing Botanical Garden in the He also intentionally collected wild jujube jubes at the USDA Chico Station continued 1990s [Xotcfruit (R. Meyer), 2013]. Jim seeds as rootstocks (Meyer, 1911) and seeds until the end of the 1950s (Ackerman, 1961). Gilbert of One Green World Nursery in from trees with good fruit flavor for cultivar Now ‘Li’ and ‘Lang’ are the two most Oregon, introduced ‘Autumn Beauty’ and breeding purposes (Table 2). Meyer men- available cultivars in the United States. ‘So’, ‘Winter Delight’TM from China (Ashton, tioned several times the hen egg-sized jujube ‘Yu’, ‘Mu’ (Mu shing hong), and ‘Shui men’ 2006) and several cultivars from the Ukraine fruit, and ‘Li’ was one of them. Of the 67 of Frank Meyer’s importation are also avail- (personal communication) and the New Mex- accessions imported, the very first one (PI able in small quantities at Fountain Valley, ico State University Sustainable Agriculture 17752) was an unknown cultivar, 35 were CA, a private collection of Roger Meyer (not Science Center at Alcalde, NM, directly vegetative parts from 34 cultivars (two ‘Wu directly related to Frank Meyer), who is imported over 30 cultivars from China in hu tsao’ from different locations), one acces- a jujube enthusiast and vice-president of 2011. Cultivar evaluation trials are greatly sion was a rooted plant from one of those 34 California Rare Fruit Growers [Xotcfruit needed across the United States to move cultivars, and another one was a sample of (R. Meyer), 2013]. jujube production forward. Growers need dried fruit; the other 29 accessions were seeds Cultivars from the USDA Chico breeding more cultivars for different purposes and to from either Z. spinosa (three accessions) or Z. program. There were several cultivars bred at extend their harvest seasons. jujuba cultivars (26 accessions). All of Frank the USDA Chico Station by Dr. Ackerman The jujube cultivars in China have Meyer’s introductions were first planted at and his colleagues, although most of them changed and increased rapidly after 1980 the USDA Plant Introduction Station at Chico were not officially released. and especially since the 1990s. Researchers and were later distributed to other USDA ‘Chico’, also called ‘GI-7-62’, bred at the have done significant work on jujube germ- stations, especially in Dalhart, Big Spring, USDA Chico Station, is a seedling of PI plasm collection and selections. An increas- and Lubbock, TX; Woodard and Lawton, 37484 (‘So’) with round but flattened fruit. ing number of new selections were named OK; Garden City, KS; and Tucumcari, NM Paul H. Thomson, who is one of two founders after 1990, but hybridization breeding is still (Locke, 1948). In the mid-1930s, J.L. Collins of California Rare Fruit Growers, named it problematic as a result of jujube’s tiny flower of the Tennessee Valley Authority tested 40 ‘Chico’ to remember the Chico Station in and the multiple flowers in a florescence (Liu, cultivars near Norris, TN, and ‘R3T1’ (Row California (Thomson, 1971). ‘GI-1183’ is 2006). There are over 800 jujube cultivars in 3, Tree 1) was a selection from that planting another cultivar from the USDA Chico Sta- China now (Guo and Shan, 2010). There are (Osborn and Miller, 2009). tion bred by Ackerman from unknown sour- total of 60 to 70 ‘‘cultivars’’ in the United In the 1920s, the USDA Chico Station ces (Ashton, 2006). ‘GA866’ is a cultivar States, but only a few of them are commer- recommended four cultivars—‘Mu shing hong’ bred and selected at the USDA Chico Sta- cially available. Hopefully, after several (PI 22684), ‘Lang’ (PI 22686), ‘Shui men’ (PI tion by Ackerman with unknown sources years of research and evaluation, we will be 38245), and ‘Li’ (PI 38249) (Thomas, 1927). (Ashton, 2006; California Rare Fruit Growers, able to recommend 10 to 20 cultivars for ‘Mu shing hong’ was described as ‘‘one of the 1996). ‘Thornless’ is a cultivar bred/selected different purposes to growers. best varieties’’; ‘Lang’ was ‘‘the best variety at the USDA Chico Station by Ackerman and for general purposes’’; ‘Shui men’ was ‘‘of Smith; the fruit shape is similar to ‘Lang’ and Taxonomy and Biology average size and useful for many purposes’’; the source is unknown (Ashton, 2006). and ‘Li’ had ‘‘the largest fruit and is one of Cultivar/selections from across the United Jujube belongs to the Rhamnaceae (Buck- the best to eat fresh and ripened one to two States. The United States does not have large thorn) family. Its close relative is the sour weeks later.’’ Coincidently, all four culti- germplasm resources (gene pool) for cultivar jujube, from which cultivated jujubes were vars were originally imported from Shanxi selection like China does, but after more than selected (Liu, 2006). Sour jujube grows in the Province. Locke (1948) mentioned three of 175 years of jujube cultivation in the United wild in the mountainous areas of northern the four cultivars without ‘Mu shing hong’. States, there are some jujube plants with great China. It is sometimes used as hedgerows,
HORTSCIENCE VOL. 48(6) JUNE 2013 673 Table 2. Jujube accessions imported from China by agricultural explorer Frank N. Meyer during 1905–18. Chinese Collecting Province/area PI no. Colleting date Plant part Name name location (now) 17752 20 Mar. 1905 Roots or bud sticks of a large- fruited N/A Chang-li, Chihli Hebeiz cultivar 17892 20 Mar. 1905 Seeds of sour jujube Suan tsao Hebei 18565 20 Mar. 1905 Seeds N/A Peking Beijing 19394 5 Oct. 1905 Seeds from market of a large- fruited N/A Peking Beijing cultivar 19397 26 Oct. 1905 Seeds N/A Pee-san Hebei (?) 20092 26 Sept. 1906 Seeds of a large-fruited cultivar N/A Vladivostok, Siberia Siberia 21618 30 Sept. 1907 Seeds Chin sze tsao Laoling, Shandung Shandong 21619 7 Sept. 1907 Seeds Yuen ling tsao Shantung Shandong 21993 Aug.–Sept. 1907 Seeds mixture from different locations N/A Shantung Shandong 21994 22 Aug. 1907 Seeds Twen ku lu tsao Chingcliowfu, Shandung Shandong 21995 19. Sept. 1907 Sour jujube seeds Suan tsao Boshan, Shantung Shandong 21996 22 Sept. 1907 Seeds Tun ku yu tsao Chinanfu, Shantung Shandong 22606 9 Dec. 1907 Seeds N/A Jehol, Chihli Hebei 22683 1 Mar. 1908 Budwood Hu ping tsao Tsintse, Shanxi Shanxi 22684 10 Mar. 1908 Budwood Mu shing hong tsao Tsintse, Shanxi Shanxi 22685 10 Mar. 1908 Budwood Tsui ling tsao Tsintse, Shanxi Shanxi 22686 10 Mar. 1908 Budwood Lang tsao Tsintse, Shanxi Shanxi 22914 1 Apr. 1908 Budwood Lung tsao tsao shu Tientsin, Chihli Tianjin 30411 10 Nov. 1912 Seeds N/A Chinese Turkestan Xinjiang (?) 31737 4 May 1911 Dried fruits, tree originally from Honan N/A Chugutchak, Mongolia Mongolia 35253 30 Mar. 1913 Cuttings Wu hu tsao Laoling, Shantung Shandong 35254 30 Mar. 1913 Cuttings Wu hu tsao Laoling, Shantung Shandong 35255 30 Mar. 1913 Cuttings Tze lin tsao Laoling, Shantung Shandong 35256 30 Mar. 1913 Cuttings Tang tsao Laoling, Shantung Shandong 35257 30 Mar. 1913 Cuttings Hsiao tsao Laoling, Shantung Shandong 35260 30 Mar. 1913 Rooted plants of 35253 Laoling, Shantung Shandong 35287 18 Mar. 1913 Sour jujube seeds Suan tsao Peking Beijing 35601 1 Apr. 1913 Seeds (scion is 35255) Tsinan, Shantung Shandong 35602 1 Apr. 1913 Seeds Pou hong ta tsao Peking Beijing 35603 1 Apr. 1913 Seeds Yuan ling tsao Tsinan, Shantung Shandong 35604 1 Apr. 1913 Seeds Ta hong tsao Tientsin Tianjin 35605 1 Apr. 1913 Seeds Ta hsiao hong tsao Peking Beijing 35606 1 Apr. 1913 Seeds Hsiao tsao Tsinan, Shantung Shandong 35607 1 Apr. 1913 Seeds Hsiao tsao Tientsin Tianjin 35608 1 Apr. 1913 Seeds Rho hsiao tsao Tientsin Tianjin 35609 1 Apr. 1913 Seeds Pou hong hsiao tsao Peking Beijing 36852 7 Nov. 1913 Budwood Ta tsao Peking Beijing 36853 8 Nov. 1913 Budwood Hsiao tsao Peking Beijing 36854 9 Nov. 1913 Budwood Yu tsao Peking Beijing 37475 23 Dec. 1913 Budwood Ta tsao Lingpao, Honan Henan 37476 24 Dec. 1913 Budwood Ta kungTsao Lingpao, Honan Henan 37484 6 Jan. 1914 Budwood So Tsao Sianfu, Shensi Shaanxi 37489 8 Jan. 1914 Budwood Lung chao tz’u shu Sianfu, Shensi Shaanxi 37659 4 Feb. 1914 Budwood Ma lieu tsao Sianfu, Shensi Shaanxi 37668 10 Feb. 1914 Budwood Ta tsao Shansi Shanxi 38187 14 Mar. 1914 Budwood Ta tsao Kuyehsien, Shantung Shandong 38243 14 Feb. 1914 Budwood Ta Yuan tsao Paihsiangchen, Shanxi Shanxi 38244 14 Feb. 1914 Budwood Tiao tsao Paihsiangchen, Shanxi Shanxi 38245 14 Feb. 1914 Budwood Shui men tsao Paihsiangchen, Shanxi Shanxi 38246 14 Feb. 1914 Budwood Chi hsin tsao Paihsiangchen, Shanxi Shanxi 38247 14 Feb. 1914 Budwood Yuan ts’ui tsao Paihsiangchen, Shanxi Shanxi 38249 14 Feb. 1914 Budwood Li tsao Anyihsien, Shanxi Shanxi 38250 14 Feb. 1914 Budwood P’o p’o tsao Anyihsien, Shanxi Shanxi 38251 14 Feb. 1914 Budwood Ken tsao Anyihsien, Shanxi Shanxi 38252 14 Feb. 1914 Budwood Kuai tsao Anyihsien, Shanxi Shanxi 38253 14 Feb. 1914 Budwood, less twisted than 38252 Anyihsien, Shanxi Shanxi 38258 27 Feb. 1914 Budwood Hui tsao Wulipu, Honan Henan 38260 27 Feb. 1914 Budwood Chui yueh ch’ing tsao Honan Henan 38261 27 Feb. 1914 Budwood Ma ya t’ou tsao Honan Henan 38359 27 Feb. 1914 Budwood Su tsao Honan Henan 39194 20 Jun 1914 Seeds Hsiang tsao Peking Beijing 40506 20 Jan. 1915 Budwood Chin tsao or Fei tsao Pinchow, Shensi Shaanxi 40877 20 Jan. 1915 Seeds of 40506 Chin tsao or Fei tsao Pinchow, Shensi Shaanxi 40878 31 Jan. 1915 Seeds of 37476 N/A Lingpao, Honan Henan 40899 5 May 1915 Seeds for rootstocks N/A Peking Beijing 44203 16 Dec. 1916 Seeds from big fruits for new selection N/A Peking Beijing 44687 16 Dec. 1916 Small fruits used for seeds as rootstocks N/A Peking Beijing zChihli was the old name for Hebei Province, China. N/A = not available in the original reference.
674 HORTSCIENCE VOL. 48(6) JUNE 2013 and local people also collect the fruits for its Flowers and fruit. Unlike apples or and develop to mature fruit within one seeds, which is a traditional Chinese herb peaches, jujubes do not have big, showy growing season, which is unique and differ- ‘‘suanzaoren,’’ or use the fruits for soft drinks flowers. Its flowers are fragrant, pale greenish ent from most tree fruit crops. Jujubes bloom or further processing. It is also sold as snacks yellow in color, and small with diameters for several weeks, making jujubes good directly when freshly picked during harvest ranging from 4 to 8 mm (Fig. 2). A jujube nectar plants for the Asian honeybee (Apis time in small quantities (Guo and Shan, flower has five sepals, five petals, five an- cerena) in China. However, in the United 2010). The fruits of sour jujube are small thers, and one ovary with two ovules (Yao, States, the western honeybees (Apis melli- and puffy without much flesh between the 2013). The five sepals are connected and fera) rarely visit the jujube flowers in New skin and the seed; however, it has higher sealed before anthesis. The anther and petal Mexico, and a jujube grower in California has vitamin C and titratable acid contents than are isometric between sepals, and the petals made a similar observation (Roger Meyer, jujube cultivars (Wang et al., 1956). Indian are spoon- or cup-like and hold the anthers personal communication). jujube, or ber, is also from the same genus until pollen-dispensing. The nectary disk Jujube fruit is a drupe with one pit (stone) (Ziziphus mauritiana) and is widely planted around the ovary is full of nectar during in the middle containing up to two seeds. Its in India and nearby countries (Baloda et al., bloom and attracts insect visitors. Flower fruit derives from its ovary and the nectary 2012). Jujubes are also known as chinese buds initiate as the branchlets grow. Flowers disk (Liu, 2006; Yao, 2013). Fruit size varies dates as a result of the similarity in appear- can appear singly or in a cluster at each leaf from thumb-sized to golfball-sized depend- ance of dried jujube fruit and dried date (date axil. Jujube’s flower cluster (inflorescence) is ing on the cultivar. The fruit shape can be palm, Phoenix dactylifera). Interestingly, the a cyme (Fig. 2) with up to 13 flowers depend- round, oblong, oval, ovate, obovate, oblate, Chinese word for date palm (‘‘zongzao’’) ing on the cultivar and its position on the apple-like, or abnormally shaped (Liu, 2006) literally means palm jujube as a result of its branchlet. Jujube flower buds initiate, bloom, (Fig. 3). Jujubes are very precocious: they similarity to jujube. Jujube is a small tree of 20 to 30 feet depending on location with strong and hard wood. Its leaves are shiny, ovate or oval in Table 3. Jujube accessions collected from 1905–18 by others excluding Frank N. Meyer. shape, not branched, and alternate. Leaves PI no. Location Presenter Cultivar Plant part are 2.5 to 5.5 cm long and 2 to 4 cm wide. 23455 Beaufort, SC F. Chisolm N/A Stock Buds and shoots. Jujube shoots are differ- 24573 Kutais Province, Transcaucasia N.E. Hansen N/A Fruit ent from other fruit species. Vigorous new 25777 Paris, France N/A N/A Stock shoots of peach, apple, and grape can have 26109 Hangchow, China J.H. Judson N/A Plant branches in the same growing season, and the 28764 Las Cruces, NM David Griffiths N/A Seeds branches have similar structure to the pri- 28926 Shandong, China T.J. League Chang hung tsao Cuttings mary shoot. Jujube has four types of shoots: 28927 Shandong, China T.J. League Yuan ling tsao Cuttings primary (extension) shoot, secondary shoot 29356 Shandong, China J.S. Whitewright N/A Roots (side branches), mother-bearing shoot (fruit- 34054 Tientsin, China Yamei Kin N/A Seeds ing spur), and fruit-bearing shoot (branchlet) 34162 Washington, DC L. Reynolds N/A Plant 34874 Peking, China N.S. Hopkins N/A N/A (Fig. 1). There are three kinds of jujube buds: 37069 Tientsin, China Yamei Kin Ya hu tsao Budwood main buds, secondary buds, and dormant 37070 Tientsin, China Yamei Kin Kang tsao Budwood buds (Liu, 2006; Yao, 2012a). 39477 China Paula Ritter N/A N/A There are two buds, one main bud and one 42046 Shorter, AL C.G. Howard N/A Cuttings secondary bud, at each node of both the 42305 Damingfu, Chihli J.G. Cole Pu tao tsao Cuttings primary and secondary shoots and at the apex 42306 Damingfu, Chihli J.G. Cole Tan tsao Cuttings of the mother-bearing shoots. The terminal 42307 Damingfu, Chihli J.G. Cole Pu tao tsao Cuttings main bud of the primary shoot will keep 42308 Damingfu, Chihli J.G. Cole Pu tao tsao Cuttings growing each season to expand the tree 42309 Damingfu, Chihli J.G. Cole Ma yu tsao Cuttings canopy, and the lateral main buds (at the base N/A = not available in the original reference. of each secondary shoot) normally do not sprout and become dormant except with strong stimulation. The secondary buds on each node of the primary and secondary shoots are early-maturing buds, which pro- duce secondary shoots or fruit-bearing shoots (Yao, 2012a). The jujube primary shoot is always accompanied by secondary shoots (side branches), or the secondary shoots are part of the primary shoot and later diverge in function. The primary shoot elongates ev- ery year to expand the tree canopy. The Fig. 1. Jujube shoot structures: (A) primary shoot, (B) secondary shoot, (C) mother-bearing shoot (young secondary shoot acts as a base for the fruiting spur), (D) old fruiting spur, (E) fruit-bearing shoot (branchlet) (Adapted from Yao, 2012a). fruiting structure, does not extend in length, and withers back after 2 or 3 years. At each node of the secondary shoot is a mother- bearing shoot (fruiting spur), which is a compact spur that grows 1 mm and pro- duces two to five fruit-bearing shoots each year. The fruit-bearing shoot (branchlet) is thin, flexible, deciduous, and 10 to 20 cm long; it bears flowers and fruits at its axils. The primary shoot, secondary shoot, and branchlet are zigzagged and spiny (Yao, Fig. 2. Jujube flowers: (A) a simple cyme, (B) a large cyme, (C) a half-opened flower, (D) a fully opened 2012a). flower (Adapted from Yao, 2012a).
HORTSCIENCE VOL. 48(6) JUNE 2013 675 normally set some fruit the second year after setting, and maturing within one growing seeds of Z. jujuba (Otsuka et al., 1978). As planting and even sometimes set fruit during season, it is not directly affected by the a result of its ability to inhibit platelet the year of planting or grafting. previous year’s weather or pest problems aggregation, jujuboside B could also be used Jujubes have morning blooming type and that, for other fruit, may have a carryover in preventive or therapeutic herbal medicine afternoon blooming type (Lyrene, 1983; Yao, effect on return bloom. for cardiovascular disease (Seo et al., 2012). 2012b). In China, a lot of dominant cultivars Jujubes are drought-tolerant (Hager and Jujube fruit is high in sugar, vitamins, were self-fruiting, some cultivars performed Edward, 1989). The tree can survive with an edible cellulose, minerals, cyclic adenosine better with cross-pollination, and a few of annual rainfall of only 200 mm, but for monophosphate (cAMP), and cyclic guano- them were self-fruitless or self-sterile with- better fruit set and fruit quality, more pre- sine monophosphate (cGMP) (Church, 1924; out pollen (Guo and Shan, 2010; Wang et al., cipitation or supplemental irrigation is Guo and Shan, 2010; Liu, 2006; Liu and 2006; Yan et al., 2010). However, cross- needed. In Tucumcari, NM, there are sev- Wang, 1991). Jujube fruit has much higher pollination always increases fruit set and eral untended jujube patches that were sugar concentration than most temperate improves fruit size, quality, and seed de- planted in the 1930s (Fig. 4). They spread fruits like apples, peaches, and grapes. The velopment. Some home gardeners have pol- by seeds or by root suckers on dryland sites soluble solids content of grapes can reach lination problems in the United States. Until without any irrigation or care and have 22% to 25%, but for jujubes, 30% soluble a thoroughly jujube fruit pollination and fruit survived for 80 years. The trees can survive solids content is not rare and some cultivars set study has been completed, it is recom- extremely dry weather and will set fruit in can reach 40% (Meyer, 1991b). Wang et al. mended to plant two cultivars for cross- wet years, which makes them good back- (1956) reported the ascorbic acid (vitamin C) pollination. There were a few reports about yard or landscape trees. content of jujube fruit to be 300 to 500 mg/ parthenocarpic cultivars, but more research is 100 g fresh weight and 800 to 1000 mg/100 g needed on this as a result of the tiny jujube Nutrient Contents fresh weight for Z. spinosa. Bi et al. (1990) flower and replication issues (Guo and Shan, tested the vitamin C content of 121 jujube 2010; Lyrene, 1983). Jujubes have been used in China as fruit cultivars and found an average of 412 mg/100 g and a traditional Chinese herb for a long time and a range from 166 to 808 mg/100 g with Jujube’s Adaptation and Culture because of their beneficial health effects, fresh-eating cultivars containing less vitamin although their nutrient composition was not C than drying cultivars. However, most of the Jujubes adapt well to a wide range of soil clear at that time. The sour jujube seeds were vitamin C gets lost during the sun-drying and weather conditions. They grow across used to treat insomnia, which could be related process, and on average only 10% remains. China except in Heilongjiang and Jilin Prov- to the jujuboside A and B in the seeds and So, for the benefit of vitamin C, eating fresh inces and the Tibet region. Jujubes grow from their sedative effect (Fang et al., 2010). jujube fruit is much better than eating dried 0 to 2000 m elevation, between lat. 18°14# to Jujuboside A and B are also found in the fruit. The USDA recommended daily vitamin C 45° and long. 76° to 124°, and in soil pH 5.5 to 8.5 (Guo and Shan, 2010; Liu, 2006). In the United States, they grow from Pennsylvania, Washington, DC, North Carolina, South Car- olina, to Florida, then from Florida, Georgia, Tennessee, Louisiana, Mississippi, Okla- homa, Texas, Kansas, New Mexico, Arizona, to California (Ashton, 2008; Brubaker, 1977; Locke, 1948; Lyrene and Crocker, 1994). Fairchild (1918) reported that jujubes could tolerate 48.9 °C in the summer in northern California and withstood –30 °C in the win- ter. Jujubes have been shown to grow and fruit well in the hot and arid southwestern United States (Locke, 1955; Meyer, 1911; Thomas, 1927; Yao, 2012a). In China, the story is similar: Hebei, Henan, Shandong, Fig. 3. Jujube cultivars with different sizes and shapes grown at Alcalde, NM, in 2012 (Photo by S. Yao). Shanxi, and Shaanxi are traditionally the five dominant jujube-producing provinces, but during the last 20 years, jujube plantings in the Xinjiang region, where the climate is hot and arid, have produced the best fruits in China with prices two to three times higher than others (Liu, 2008). Because jujubes like full sunshine and tolerate hot weather, the southwestern United States is an ideal loca- tion for jujubes where the arid climate also restricts many disease problems. Numerous authors have mentioned the reliability of jujubes as a crop (Fairchild, 1918; Hager and Edward, 1989; Lanham, 1926; Locke, 1948; Lyrene, 1979; Meyer, 1916; Thomas, 1927; Yao, 2012a). With its late-season start-up, it avoids much of the late frost threat and, as a result, jujube trees rarely Fig. 4. Eighty-year-old, naturally spreading jujube patch at Tucumcari, NM, 2012. There were several miss a crop. Jujube normally leafs out 4 to patches there ranging from 0.2 to 0.5 ha each. The few old original plantings could still be seen in the 6 weeks later than most temperate tree fruit middle and they spread out naturally by seeds or by root suckers. They might have set fruit during years crops and it blooms even later and continues with heavy rainfall, but during most years, they likely set few fruit and struggled to obtain enough blooming for 2 months or longer. Because it water without irrigation. The average annual precipitation at Tucumcari is 409 mm. The species is finishes flower bud initiation, blooming, fruit Z. jujuba with small fruit (Photo by S. Yao).
676 HORTSCIENCE VOL. 48(6) JUNE 2013 requirements are 90 mg for men and 75 mg most popular propagation method. T-budding, The most important insect problem on for women, and based on the average vitamin which is popularly used in pome and stone jujubes in China is peach moth (Carposina C content, 20 to 30 g of fresh jujube/day (one fruit propagation, does not work well for nipponensis) damage to fruit. There are also to three fruit depending on the fruit size) jujubes as a result of their shoot and bud other insects that damage leaves. In the would meet this requirement. structure and their thin bark. Whip tongue United States, the pest and disease pressure Cyclic adenosine monophosphate was grafting, bark grafting, and cleft grafting for jujubes is low at this time. Most re- first isolated from jujube fruit in 1980 (Cyong are the most popular and successful graft- searchers in the United States mentioned that and Hanabusa, 1980) and cGMP in 1982 ing methods (Guo et al., 1994). Whip there were no pests and diseases for jujubes (Cyong and Takahashi, 1982). It was found grafting requires that the diameters of the thus far (Ashton, 2006; Locke, 1955; Lyrene, that cAMP and cGMP from jujube fruits had scionwood and rootstock are similar. This 1979). We have yet to see disease problems the same physicochemical properties as pure grafting method is the most difficult to in New Mexico, but we occasionally noticed cAMP and cGMP. The cAMP content of perform, but it can use the small rootstocks, peach moth damage to the sour jujube fruit jujube fruits ranged from 100 to 150 nmol·g–1 and windbreak is rare after grafting. Bark that was collected in Las Cruces, NM, for of fresh fruit and from 100 to 600 nmol·g–1 of grafting needs to be done in the growing seeds that will be used for rootstocks. In dried jujube fruit, and the cGMP content was season when the cambium layer is active, California, growers have complained about 30 to 60 nmol·g–1 dried fruit and it increased and its operation is easier than whip graft- bird damage to fruit (Roger Meyer, personal 90 times as the fruit ripened (Cyong and ing. Cleft grafting and side grafting can communication). Takahashi, 1982; Qu et al., 1987). Liu and also be used in addition to bark and whip Wang (1991) reported the highest cAMP in grafting; cleft grafting is used with big Jujube-related Research in the United jujube cultivar Muzao at 303 nmol·g–1 fresh rootstocks, and side grafting can be used States weight (756 nmol·g–1 dry weight), which is in warmer areas. With jujube’s hard wood the highest known in higher plants. Cyong and lack of T-budding, jujube grafting is Formal jujube research started when the and Hanabusa (1980) found jujube cAMP more challenging than other fruit tree spe- big-fruited cultivars were imported to the content 10 times higher than all other fruit cies. However, with a combination of whip USDA Plant Introduction Station at Chico, tested. Zhao et al. (2009) studied the cAMP grafting and bark grafting around tree bud- CA, in 1908. Scientists evaluated the im- and cGMP contents in different jujube culti- ding time and several weeks after that, the ported cultivars, propagated them at Chico, vars, development stages, and organs. The author achieved 95% grafting success in dispersed them to other USDA stations for cAMP is a second messenger in our body, and northern New Mexico. evaluation (Locke, 1948), recommended cul- the jujube fruit could be used as a natural The majority of jujube plants sold from tivars, tested their nutrient value, researched source of cAMP (Li, 2012). (As for cAMP’s nurseries now are grafted plants on sour their pollination and fruit set (Ackerman, 1961), medical effects, please refer to Serezani et al., jujube rootstocks. However, for those scat- and conducted jujube cultivar breeding/ 2008.) tered old plantings in people’s backyards, selection. Bonner and Rudolf (1974) tested Jujube fruit also have high total phe- some are on their own roots and their suckers jujube and sour jujube seed germination nol contents and total antioxidant activity are identical with the mother plants, which and found that jujube and sour jujube seeds (Kamiloglu et al., 2009; Li et al., 2005). In the can be used directly for planting. This is could germinate directly, but stratification 1920s, people paid attention to sugar and especially useful for home gardeners who for 2 to 3 months increased the germination protein content and compared jujubes with want to get a jujube plant from friends or rate; water soaking at 21 to 37.8 °Cfor dried palm date and figs (Church, 1924). Cur- neighbors. 2dalsopromptedZ. spina-christi seed rently, with higher health awareness, people germination. Outlaw et al. (2001) studied pay more attention to the benefits fruit pro- Pests and Diseases the jujube nectar composition and found it vides, like ascorbic acid, phenols, anti- was dominated by sucrose with 40% total oxidants, and medicinal effects. Consumers The dominant jujube diseases in China are sugar content. Jujube flowers attracted 18 would accept jujube fruit much easier than witches-broom and fruit splitting/cracking. species of insects, including bees, flies, and in the 1920s. It is expected that the jujube Witches-broom is widespread in jujube- beetles, but honeybee numbers were not high commercial production era could be immi- producing areas in China, Korea, and Japan in the netted insects. Kader et al. (1982) nent in the United States. (Guo and Shan, 2010; Jung et al., 2003; Zhou studied the postharvest storage of jujubes at et al., 1998). It can wipe out a whole orchard, the University of California–Davis and found Jujube Propagation and there is no cure except for preventive that jujubes were high in sugar and total management. Witches-broom is caused by a phenols but low in titratable acid. They also Jujube grafting has been recorded in the phytoplasm, ‘Candidatus Phytoplasma ziziphi’ indicated that jujube’s high ascorbic acid puts oldest Chinese farming book, ‘‘Qi Min Yao (Jung et al., 2003). The leafhopper species it near the top of the list of fruits for vitamin C Shu’’ (Essential farming skills for the com- Hishimonus sellatus Uhler (RLH) (Doi et al., sources. The jujube fruits were stored at 0 °C mon people), which was published 1400 1967), Hishimonoides chinensis (Wang et al., for 26 d and exhibited chilling injury of years ago (Guo and Shan, 2010). However, 1984), Hishimonodies aurifavialea,and pitting (Kader et al., 1982). Lyrene (1983) in practice, the most widely used method of Typhlocyba sp. (Chen et al., 1984) were re- observed 18 jujube cultivars flowering and jujube propagation was by root suckers in ported as vector insects for jujube witches- fruiting in Florida and noticed two blooming China until the 1960s. After the 1980s, as broom disease. types with varied fruit set. He concluded the more new cultivars were selected and re- Fruit splitting/cracking is a water-related heavily fruited cultivars were parthenocarpic leased, jujube grafting with sour jujube physiological disorder that can ruin the whole such as ‘Silverhill’ and ‘Leon Burk’, which rootstocks became increasingly popular. crop in some extreme years. The severity of were recommended for the southeast United In traditional jujube-growing regions, peo- the problem depends on water management States. Sweet (1985) discussed jujube culti- ple still used root suckers to propagate during the growing season, precipitation vars, propagation, and production in his because their trees were from root suckers around the fruit maturation season, and cul- article and predicted a large market potential and their new suckers still produced fruit tivar resistance to splitting. Guo and Shan for Chinese jujubes in the United States. identical to the mother plants. In new pro- (2010) mentioned that serious splitting and There were quite a few people across the duction areas, plants were grafted and the fruit rot happened once every 5 years with country from the North American Fruit Ex- suckers only used as rootstocks for grafting, 40% fruit loss in Laoling County, Shandong plorers group who tested jujubes in their own not directly for planting. Researchers also Province. Maintaining a stable water supply yards or orchards. In general, jujube research tried softwood cuttings (Sheng et al., 2008) during the growing season will ease splitting, is very limited in the United States, and there and tissue culture propagation of jujubes but the cultivar is what makes the ultimate are almost no research publications after (Wang et al., 2009), but grafting is still the difference. 2001.
HORTSCIENCE VOL. 48(6) JUNE 2013 677 Jujube Uses/Processing Products fully covered with liquor. They are then China. Its seeds, especially the seeds from sealed in jars or zip bags and can be stored Z. spinosa, are a famous traditional Chinese When jujube fruits are close to maturity, for 6 months to 1 year. They can also be herb, ‘‘Suanzaoren’’ (Qu et al., 1987). Its their skin color turns from dark green to light sealed in small packages and sold directly in wood is very hard and good for instruments green/creamy with high vitamin C content those packages several months later (Guo and or utensils. (white mature stage). The soluble solid con- Shan, 2010). tent measures 20% for most cultivars. The Smoked jujube. This product is mainly Challenges and Opportunities: Why Not fruit then change color and become half produced from the cultivar Yuan ling tsao in an Industry Yet? cream/half red and eventually turn fully red/ Shandong Province. Fruits are picked at the brown (crisp mature stage). At this stage, the fully red stage, precooked in boiling water, When jujubes entered the United States, fruit becomes crispy, sweet, and juicy with and then smoked. The product can be eaten Frank Meyer and other researchers who high sugar and acid content. The fruit skin directly or used in cooking. worked with jujube were impressed with gets thicker, harder, and easier to separate Roasted jujube. Red dates are used for this jujube’s fruit quality and nutrient content, from the flesh after boiling. Fruit have the purpose. The fruit are first pitted and then wide adaptability, reliability, lack of frost best fresh-eating quality at this point, but sliced vertically to pieces 3 mm wide damage, drought tolerance, and easy care the vitamin C content starts to decrease. before roasting. Fully mature fresh fruit of (Lanham, 1926; Meyer, 1911). They pre- After that, the skin of the fruit will wrinkle drying cultivars can also be used but require dicted a bright future in the United States, and start to dehydrate and the flesh color a longer roasting time than using dried fruit. especially in the Southwest (Lanham, 1926). near the kernel changes from greenish white Jujube jam. Full red fruits are also used There was another round of interest in jujubes to yellow/light brown and turns soft. Sugar for jam, which can preserve 65% to 80% of beginning in the 1980s, especially among and acid contents continue to increase, and the vitamin C content. The fruit needs to be the members of the California Rare Fruit vitamin C content continues to decrease (fully skinned and pitted for this purpose. Growers and the North American Fruit Ex- mature stage). Depending on the purpose, Jujube paste/filling. Jujube filling is plorers. Growers and home gardeners had big jujube fruit can be picked from the white widely used in the pastry industry in China; interests in jujubes and wanted to promote mature stage, to the crisp mature stage, or the it is one of the traditional fillings of moon- jujubes in the United States. Roger Meyer fully mature stage. Fresh-eating cultivars can cakes (Guo and Shan, 2010; Yao, 2012a). It wrote a series of papers about jujube culture, be picked from the white mature stage until can also be directly spread over bread. propagation, fruit use, and cultivar collection the crisp mature stage when the fruit texture Jujubes can also be used to make juice, (Meyer, 1988, 1989, 1991a, 1991b, 1994; is still firm. wine, and vinegar, whereas the red date is Meyer and Meyer, 1994a, 1994b). Jujube was Red date (dry date). Red date is the also widely used in the culinary world. the ‘‘Fruit of the Year’’ for the California dominant jujube product for the domestic The Chinese and Southeast Asian popu- Rare Fruit Growers in 1994 (Guggenheim, and export markets in China. Fruits are lations in the United States are used to having 1994). However, lack of research support, picked when they are fully red or the fully jujubes in their diets, consuming them fresh, propagation hurdles, limited cultivars, and mature stage because the more mature they dried, or processed. If we promote jujubes lack of marketing, promotion, and American- are, the higher their sugar content and drying and want the rest of Americans to consume style products all restrict jujube’s adoption in quality. After picking, fruits can be air-, sun-, them, American-style jujube products are the United States. or heat-dried. Heat drying is the optimal needed. There are a few recipes listed at After hosting a ‘‘jujube-growing habits method because it retains more vitamin C, Ashton (2006), California Rare Fruit Growers and pruning workshop’’ in the spring and leads to better fruit quality, and avoids (1996), and Guggenheim (1994). ‘‘jujube flowering, fruiting, and fruit-tasting disease-related fruit losses. Red date can be Eating fresh would be the easiest way for workshop’’ in the fall for 3 years, more and consumed directly as snacks; used in por- Americans to accept the fruit. The author more people are interested in jujubes in New ridge, stew, soup, or tea; or processed further conducted some jujube fruit-tasting work- Mexico and the nearby states. Currently, as jujube paste or other products. ‘‘Zongzi’’ is shops, including the New Mexico State Fair, nurseries have a hard time meeting the jujube a traditional Chinese food that is consumed and with school kids through the Cooking plant demands. Realizing the challenges for near the Dragon Boat Festival to remember with Kids program in Santa Fe, NM. Most commercial jujube production, these areas the patriotic poet, Qu Yuan. Red dates are people who tasted the fruit liked them. Fresh are what scientists should focus on; pomolo- placed in the middle of sweet rice, which is jujubes have an apple-like texture without gists should conduct research on pollen then wrapped by bamboo or reed leaves and any strong flavor and are sweet and nutri- germination, fruit set, cultivar regional trials, cooked for 2 to 3 h. After the cooking tious. With a good promotion program, it and culture practices with the goal of recom- process, the red date is sweet, tasty, and gives would not be difficult for the public to accept mending more cultivars to the growers. Ex- the surrounding glutinous sweet rice great this nutritious fruit. Fresh fruit can also be tension specialists should write more jujube flavor. The red dates of small-sized cultivars used solely in pie or together with apples. It publications, educate the public, and guide like ‘Jin sze tsao’ and ‘Wu hu tsao’ (pitless) seems the ascorbic acid preserved well for the commercial jujube production. Food are excellent when cooked with rice or millet products cooked with fresh fruit (S. Yao, scientists should experiment with American- in porridge (Meyer, 1911). unpublished data), which would be beneficial style jujube products while agricultural Candied jujube (honey jujube). Frank because people have more concern about marketing specialists work on jujube pro- Meyer (1911) mentioned the cooking process health than before. Fresh fruit can also be motion and marketing. Growers can start of honey jujubes, which have been popular in used in ice cream or fruit salad or processed small and expand gradually. With big cities China for 200 years. Fruits are picked at into jam. like San Francisco and New York, it would white mature stage and 60% to 80% of Dried jujubes can be directly used in fruit be an easy start through targeting the Asian vitamin C content can be kept, which is much and nut mixes or used to replace raisins or population and Asian markets with fresh fruit higher than the sun-dried jujube. Fruit sur- palm dates in baking for cakes, tarts, or other or dried fruit (red date). As more and more faces are sliced with rows of blades or pastry products or baked goods. Jujube paste people come to know this exotic fruit, free needles to enhance sugar-soaking and prod- can be used directly as a spread or used as sampling at local markets would enhance uct appearance (Guo and Shan, 2010). filling for other pastries. A popular product is customers’ acceptance. The basic foundation Spirited jujube (‘drunk’ jujube). Fruits are needed to promote the jujube and to develop is solid: with jujube’s wide adaptation to soil picked during the fully red stage and 60% to a viable market. and weather conditions, it does grow and 70% of the vitamin C content is preserved. Jujube is also a multipurpose plant (Outlaw produce well in the southern and southwest- Spirits of 130 to 140 proof or good-quality et al., 2002). Except for its fruit, jujube ern United States with excellent fruit quality. hard liquor is used for this product. The is a nice nectar plant with a long bloom- Jujube is an excellent backyard tree for home jujube fruits are poured into the liquor and ing period and jujube honey is popular in gardeners, serving dual purposes for its fruit
678 HORTSCIENCE VOL. 48(6) JUNE 2013 and tree. With continuous research and ex- 2012.
HORTSCIENCE VOL. 48(6) JUNE 2013 679 of jujubosides A and B, the saponins isolated Nos. 34093 to 34339. USDA Bur. Plant Ind. Washington, DC. 28 Dec. 2012.
680 HORTSCIENCE VOL. 48(6) JUNE 2013